C For Loops

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In programming, a loop is used to repeat a block of code until the specified condition is met.

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For Loop

When you know exactly how many times you want to loop through a block of code, use the for loop instead of a C While Loops

Syntax

for (initializationStatement; testExpression; updateStatement)
{
    // statements inside the body of loop
}

How for loop works?

• The initialization statement is executed only once.
• Then, the test expression is evaluated. If the test expression is evaluated to false, the for loop is terminated.
• However, if the test expression is evaluated to true, statements inside the body of the for loop are executed, and the update expression is updated.
• Again the test expression is evaluated.

This process goes on until the test expression is false

Note: testExpression it’s made by C Comparison Operators and C Logical Operators.

For loop Flowchart

Example 1:

// Print numbers from 1 to 10
#include <stdio.h>
 
int main() {
  int i;
 
  for (i = 1; i < 11; ++i)
  {
    printf("%d ", i);
  }
  return 0;
}

Output: 1 2 3 4 5 6 7 8 9 10

Example 2:

// Program to calculate the sum of first n natural numbers
// Positive integers 1,2,3...n are known as natural numbers
 
#include <stdio.h>
int main()
{
    int num, count, sum = 0;
 
    printf("Enter a positive integer: ");
    scanf("%d", &num);
 
    // for loop terminates when num is less than count
    for(count = 1; count <= num; ++count)
{
        sum += count;
    }
 
    printf("Sum = %d", sum);
 
    return 0;
}

Oputput: Sum = 55

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